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<H1>IBM Visualization Data Explorer Programmer&#39;s Reference</H1>
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<H3><A NAME="HDRDXSRN" HREF="progu097.htm#PToC_418">DXSetResolution,
DXGetCameraResolution</A></H3>
<A NAME="IDX2102"></A>
<A NAME="IDX2103"></A>
<A NAME="IDX2104"></A>
<A NAME="IDX2105"></A>
<P><STRONG>Function</STRONG>
<P>
Set or retrieve the resolution of a Camera.
<P><STRONG>Syntax</STRONG>
<BR>
<TT><STRONG><BR>
&#35;include &lt;dx/dx.h&gt;<BR>
<P><BR>
Camera DXSetResolution(Camera c, int hres, double pix_aspect)<BR>
Camera DXGetCameraResolution(Camera c, int Xresolution, int Yresolution)<BR>
</STRONG></TT><BR>
<P><STRONG>Functional Details</STRONG>
<P>
A
Camera defines the position orientation of the viewer, the volume
of interest of the object being viewed, and the size of the image to
contain the resulting view.
<P>
The horizontal size of the image containing the resulting view is
defined by the
<TT><STRONG>resolution</STRONG></TT> in pixels; the vertical size is determined
by the
<TT><STRONG>resolution</STRONG></TT> * <TT><STRONG>aspect</STRONG></TT>.  This
is
camera <TT><STRONG>aspect</STRONG></TT>, not
<TT><STRONG>pix_aspect</STRONG></TT>; see
<TT><STRONG>DXSetPerspective</STRONG></TT>
and <TT><STRONG>DXSetOrthographic</STRONG></TT>.  The
same aspect ratio is used for both the size of the image and the
volume of the interest to prevent the objects from being stretched in
one of the dimensions.
<P>
If the display pixels are not square, <TT><STRONG>pix_aspect</STRONG></TT>
can be used to compensate.
Pixels are not square when the ratio of the number of pixels in the
x and y dimensions does not equal the width&#58;height ratio
of the screen.
<P>
<TT><STRONG>pix_aspect</STRONG></TT> prevents objects from appearing
stretched in one dimension (e.g. preventing a circle from
becoming an ellipse on a screen with rectangular pixels).
Pixels are assumed to be <TT><STRONG>pix_aspect</STRONG></TT> times as tall
as they are wide.
Most screens have square pixels and it is rarely necessary to set
<TT><STRONG>pix_aspect</STRONG></TT> to a value other than 1.
<P>
<TT><STRONG>DXSetResolution</STRONG></TT>, for camera
<TT><STRONG>c</STRONG></TT>, sets the horizontal resolution to
<TT><STRONG>hres</STRONG></TT> and the pixel aspect ratio to
<TT><STRONG>pix&#95;aspect</STRONG></TT>.
<P>
<TT><STRONG>DXGetCameraResolution</STRONG></TT>, for camera
<TT><STRONG>c</STRONG></TT>,
if
<TT><STRONG>Xresolution</STRONG></TT> is not
<TT><STRONG>NULL</STRONG></TT>, returns the
<TT><STRONG>resolution</STRONG></TT> in
<TT><STRONG>*Xresolution</STRONG></TT>.
If
<TT><STRONG>Yresolution</STRONG></TT> is not
<TT><STRONG>NULL</STRONG></TT>, returns the
<TT><STRONG>resolution</STRONG></TT> * <TT><STRONG>aspect</STRONG></TT> in
<TT><STRONG>*Yresolution</STRONG></TT>.  Again, this is camera
aspect.
<P><STRONG>Return Value</STRONG>
<P>
<TT><STRONG>DXSetResolution</STRONG></TT> returns the Camera or returns
<TT><STRONG>NULL</STRONG></TT> and an error code.
<P>
<TT><STRONG>DXGetCameraResolution</STRONG></TT> returns the parameters or
returns <TT><STRONG>NULL</STRONG></TT> and sets an error code.
<P><STRONG>See Also</STRONG>
<P>
<TT><STRONG>
<A HREF="progu160.htm#HDRDXGCMP">DXGetCameraMatrix, DXGetCameraRotation,
DXGetCameraMatrixWithFuzz</A>,
<A HREF="progu246.htm#HDRDXNCA">DXNewCamera</A>,
<A HREF="progu292.htm#HDRDXRNDR">DXRender</A>,
<A HREF="progu319.htm#HDRDXSOC">DXSetOrthographic, DXGetOrthographic</A>,
<A HREF="progu323.htm#HDRDXSPE">DXSetPerspective, DXGetPerspective</A>,
<A HREF="progu328.htm#HDRDXSVW">DXSetView, DXGetView</A>
</STRONG></TT>
<P>
<A HREF="progu081.htm#HDRCAMSEC">16.7 , "Camera Class"</A>.
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